H2 Rates over 1.2 in rollover factor

A vehicle's stability is measured by the formula---t/2h---where t is the 'track width' (center of the right front tire to the center of the left front tire) and h is the vehicle's center of gravity. When this number is 1.2 or greater, the vehicle is unlikely to roll according to government testing. However, the further the ratio dips below 1.2, the greater the likelihood of rollover.

While many vehicles have safe ratios, the addition of passengers, cargo and a full tank of gas all occurs above the center of gravity, increasing the chance of a rollover accident. Given a real world scenario, the SUV would probably have cargo, multiple passengers, etc. This extra weight would definitely lower the ratio to dangerous levels if an accident were to occur at normal highway speeds.

While the2005 Hummer H2 was not tested by the government, it has a track of 69.4 inches front and back, and a center of gravity (h) rating of 25.5 inches empty with full fuel, giving it a rating of 1.36 and one of the highest vehicle stability ratings of any SUV you can buy if you exclude the H1 and Subaru Forester. If you add four 170 pound passengers and 80 pounds of cargo the center of gravity (h) goes to 28.3 inches giving it a rollover factor of 1.22 - still in the unlikely to roll range and the second best rating of the 10 large SUVs listed in this table.
http://www.suvrollovernews.com/html/formula.html

35% of all SUV deaths occur from rollovers and 90% of those rollover occur when the vehicle leaves the pavement. 65% of all SUV deaths, and 87% of all car deaths occur from car to car impact, or car to fixed or moving object impact, drowning or fire. When the 65% rate is considered the H2 comes out almost at the top of the list as the safest vehicle you can buy behind the Ford Expedition in terms of deaths per vehicle. There are no acutal statistics, but it is believed that because Hummer H2s take part in offroad events to a larger extent than any other vehicle except Jeep, if offroad rollovers are discounted, the Hummer H2 has a stellar record compared to almost any other SUV.
http://www.census.gov/compendia/statab/cats/transportation/motor_vehicle_accidents_and_fatalities.html
http://www.car-accidents.com/rollover-auto-accidents.html

One final thought, many owners put larger tires and rims on their H2s for looks and for offroad capability. By going to just a two inch larger diameter tire the center of gravity is raised one inch with little effect on track, making the SUV more likely to roll over. (CNN Warrior-one report)